Adhesive coated fabric and barrier coating composition therefor



June 27, 1944- E. P. wNzELBERGr-:R ET AL 2,352,463

ADHESIVE COATED FABRIC AND BARRIER COATING COMPOSITION THEREFOR "nu u n.. u n n June 2-7, 1944- E. P. WENZELBERGER ET Al. 2,352,463

ADHESIVE COATED FABRIC AND BARRIER COTING COMPOSITION THEREFOR 2 vSheets-Sheet 2 Filed June l5, 1940 amm evalen/fag.'

5PM/mme' Patented June 27, 1944 COATING COMPOSITION THEREFOR Elwood Paul Wenzelberger, Plainfield, and Frank Nason Manley. Highland Park, N. J., assignors to Johnson Johnson.

a corporation of New Jersey NewV Brunswick, N. J.,

Application June 15, 1940, Serial No. 340,842 2 Claims. (Cl. 117-80) The invention relates to iiexible coated fabrics coated on one side with a normally tacky or pressure-sensitive adhesive and intended for use as surgical dressings. insulating wrappings, decorative and other wall coverings, and for many other purposes, and it comprises the improve- -ments hereinafter described and claimed.

Whether the fabric be of the close woven type. as is generally the practice in the manufacture of tape and plaster backings in the surgical iield and with certain classes of industrial tape, or whether it be of relatively open or coarse construction, as is the case with burlap and kindred fabrics, or whether it be manifested as a relatively thick fabric with a pitted or irregular surface, such as. for example, asbestos cloth and the like, or whether it be a web ofunspun iibers or unwoven fibers, such as paper, felt, bonded cotton, etc., all of which things are mentioned by way of illustration, and not of limitation, of conventional or any suitablebacking fabrics to which our improvements are directed, there are definite problems either from the standpoint of production or from the standpoint of the varying conditions in the service for which it is intended.

'I'he conventional cloth or fabric-backed tape because frayed edges militate againstycleancut or symmetrical line finish as in `painting with a spray gun.

For some purposes it is desirable that the coated cloth or fabric be elastic in the sensexthat it be capable of distension under applied eii'ort and of returning to the original dimension when the effort is released. The conventional v'fabric does not possess these properties.

The principal object is to -obviate the defects and disadvantages of the old practice and to provide a product, and method of making it, which will satisfactorily meet all of the requirements in an advantageous way.

While the nature and characteristic features of the invention will be set forth with more particularity in connection with the description oi' the drawings forming a part hereof, it may here;v be remarked that in one aspect the invention comprises interposing a iiexible barrier sheetor baille between the fabric and the adhesive to prevent the latter from substantially striking through the fabric as well from the standpoint of-saving of adhesive mass and the avoidance of messy conditions as also to promote the elasticity of the fabric without substantially increasing its weight; in another aspect the invention is is a porous material with voids of varying size dependingupon the choice of backing. Thermoplastic and water soluble adhesives are normally heat-sensitive and, when pressure is appliedl to a finished tape, iiowing takes place and the adhesive is pushed through the backing of the fabric and is exposed on the other side so that. for example, in the binding of the ankle it frequently happens that the outside of the dressing sticks to the stocking. Flowing of the adhesive also ensueswhen the conventional tape or plaster is subjected to elevated temperatures for sterilizlng purposes. The conventional fabric-backed pressure-sensitive adhesive cannot withstand wetting. When wetted the adhesion between the fabric and the adhesive mass is weakened to a point which is less than the adhesion between the adhesive mass and the object to which it is applied. Moreover, under the conventional practice the adhesive mass is permitted more or less to enter and fill the voids of the fabric backing and this, in enect caulking, makes for sheer waste of relatively expensive adhesive mass.

Another defect and disadvantage of the conventional fabric is its tendency to ravel, a condition frowned upon in surgery and which in certain mechanical uses is highly objectionable comprehends a flexible barrier sheet of a type and composition that is compatible'with the adhesive mass and which readily lends itself to applicatlon as in any suitable way which will provide a continuous gossamer-like film that clings tenaciously to the surface nap or' fibers of the backing without any appreciablel tendency to migrate and penetrate into either the adhesive mass and affect its characteristics or into the fabric and stiiien the body structure as a whole or the lattice elements thereof whereby the fabric, vif naturally of distensible character, may be readily distended and upon release ofv distensible effort caused to return to its previous dimensions under the aggressive rebound action of tiie barrier sheet; in another aspect the invention comprises a continuous iilxn or sheet of rubber latex along with a backing of any desired fabricso re# lated to the sheet or iilm of rubber latex that the composite article is free from raveling and may be' divided at vany point or trimmed along the margins without the hazard of leaving frayed edges; in another aspect the invention comprises such composite article-having on the'rubber latex side an applied flexible surface coating of normally tacky or pressure-sensitive adhesive; in another-aspect the invention comprises such compositey article having on the rubber latex side an applied flexible surface coating of pressuresensitive adhesive embodying the composition hereinafter more particularly described.

Referring to the annexed drawings:

Figure 1 is a diagrammatic layout showing the general arrangement of the barrier sheet, the adhesive mass. and the backing.

Fig. 2 is a top view of a fabric section broken away to show a woven backing, the barrier sheet.

and the adhesive.

Fig. 3 is an enlarged sectional view of the complete fabric structure, Fig. 2, as viewed in the direction of the arrows 3 3.

Fig. 4 is a perspective view showing how the composite structure readily lends itself to knife cutting or trimming without the hazard of frayed or raveled edges.

Fig. 5 is a face view broken away showing a composite structure employing a bias fabric.

Fig. 6 is a plan view of a first-aid or emergency dressing which incorporates the composite a'rticle of our invention.

Fig., 7 is a view, more or less diagrammatic, indicating how bulk strip material according to our invention is cut on the bias to provide stretchable first-aid units.

In the practice of our invention we provide a continuous sheet or film of compounded rubber, preferably rubber latex or artificial dispersions of rubber, so treated as to be stable and compatible and to manifest pliability or stretch and rebound properties when backed, as is contemplated, with a textile or equivalent porous or mesh fabric, and then surface coated with a normally tacky or pressure-sensitive adhesive mass. This provision is made. as indicated at the outset, to serve as a barrier or bame between the adhesive mass and the backing fabric in order to prevent unnecessary loading of the backing fabric by the adhesive ahd breakdown of the adhesive due to its migration or to the migration of one or more of the constituents of the barrier.

The elastic or pliable barrier sheet or nlm, generally designated at B, may be backed with any suitable fabric 0; The filming to produce the barrier sheets may be done by knife spreading, roll coating or by any other suitable well-known practice. The backing fabric may be a relatively close woven'material, a coarse woven material or any conventional flexible material according to the service for which the article is intended.

In certain early experiments having for their ultimate purpose the provision of a barrier or baille between the cloth or backing fabric and the rubber adhesive mass to prevent absorption of the'latter, or some of its components, by the backing, we employed uncured rubber and various mineral fillers, such as zinc oxide, clay, superfioss. etc. etc. The compound was calender@ onto the cloth in a thickness equivalent to about 1 oz. to the sq. yd. and then coated with the adhesive mass in the usual way. In every instance there was a denite drying action accompanied by losa of tackiness presumed to be due to an intermingling or selective action between the two `compositions i. e. between the mass and the barrier. e Subsequently, vulcanizing agents were added to the uncured and filler compound and filmed in the described manner. However, we still found an intermingling but at a slower rate.

`Our next trial was made with rubber latex compounded with vulcanizing agents and iillers. The rate of intermingling was retarded and the extent of intermingling was reduced to a point where it was negligible. It appears that rubber 60% latex 334 parts-200 parts rubber Karaya gum (2.5% sol.) 160 parts M cNamee clay 100' parts A typical vulcanizing compound according to I our invention comprises Zinc oxide 1 Sulfur 1 Butyl zimate L 1 Darvan 0.12 Casein 0.12 Caustic soda 0.10 Water 2.66

The latter mixture in a colloidally ground'and dispersed state is added, in the proportion of l2 parts to 100 parts of rubber existing as 60% rubber latex mixture. We may vary this proportion or the ingredients depending upon the conditions or requirements at hand. The compound as heretofore remarked is spread onto the backing `in liquid form in any conventional way as, for

example, by means of a knife, roll coater, etc.

A typical spread after drying and vulcanizing with heat for about 30 minutes, at 200 F., amounts to one-half to 1 oz. per sq. yd. dry coating. A surface application of pressure-sensitive adhesive mass is then made in the conventional way. A typical application would be about 2 to 3 oz. per sq. yd. Accelerated ageing tests were conducted on strips of this material using Geer oven and air bomb for various periods of time. The ageing tests represented, over all, a period of about two years natural ageing. Upon observing the samples after these tests they were still in excellent condition Whereas the conventional adhesive tape controls had deteriorated due mainly to the mass soaking into the cloth and drying up.

Our invention is especially meritorious when embodied in tape intended for surgical uses and required to be sterilized by exposure to sterilizing heat.

Fig. 2 graphically shows the composite structure comprising the barrier sheet 5, the backing 6 and the adhesive 1 applied as a facing to the barrier sheet.- The backing fabric may be any porous sheet material and preferably a woven material.

Fig. 3 shows the distinct planar construction, that is to say. how the barrier sheet is interlocked in a substantially continuous plane with the surface loops of the backing fabric or, in other words, how it is` substantially confined to the surface thereof and how it constitutes acomplete barrier or baille to prevent flow of the adhesive mass into the backing,

y Fig. 4 illustrates that by reason of the com- 70 plete bond or interlocking relation between the barrier sheet and the backing there is no tendency towards fraying or raveling when thearticleJ Fig. 5 shows an embodiment of the invention in which the inherent stretch and rebound characteristics of the barrier sheet are aided and abetted by a bias construction backing fabric 9.

Fig. 6 shows the application of the invention t0 surgical bandage dressings ofthe emergency or ilrst-aidtype. In this more or less conventional showing the numeral I0 designates a soft pad or dressing, II a facing of pressure-sensitive adhesive, I2 the -barrier sheet, and I3 the backing fabric which, for example, may be the bias arrangement indicated in Fig. 5 or any other appropriate fabric.

In a continuation of the inventive thought of providing for increased extensible or elongation capacity in the backing fabric so that it will coordinate in the stretch and rebound action of the barrier sheet, we may proceed as shown in Fig. 7. According to this practice a strip oi' surgical bandage material comprising a suitable backing fabric I 4, a barrier sheet I 5, pressure-sensitive adhesive mass I8, pad material I'I and a protective facing, such as crinoline I8, is bias out, as at I9. to provide complete first-aid units 20.

Having described our invention, we claim:

1; A pressure sensitive adhesive tape comprising in combination a flexible backing; a normally tacky pressure sensitive adhesive mass overlying one face of said backing: and a. continuous, im-

perviou's. rubber barrier coat formed.-from. an`

aqueous dispersion of a latex rubber coextensive" with and interposed between said adhesive mass and said backing and substantially coniined to the surface of saidvbacking for preventing penetration of said mass into said backing. said latex rubber coat having the propertyot-preventing migration or intermingling of the componentparts of said mass and said barrier coat into each other whereby the eil'ective life of the adhesive" mass is prolonged. l

2, A pressure sensitive adhesive tape eomprising in combination aexible backing; :a normally tacky pressure sensitive adhesive mass overlying one face oi said backing; and a continuous, im-

pervious, rubber barrier coat formed from an said adhesive mass and said backing and substantially coni-ined to the surface of said backing' for preventing penetration of said mass into said backing, said latex rubber coat having the prop- 'erty of preventing migration or interminglingot the component parts ofsaid mass and said barrier coat into each other whereby the eil'ective life of the adhesive mass is prolonged.

l ELWOOD PAUL WENZELBERGER.

FRANK NASON MANLEY. 

